std::sqrt

From Cppreference

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Defined in header <cmath>
float       sqrt( float arg );
double      sqrt( double arg );
long double sqrt( long double arg );

Computes square root of arg.

[edit] Parameters

arg

-

floating point value

[edit] Return value

square root of arg.

Domain error occurs if arg is negative. NAN is returned in that case.

[edit] See also

cbrt (C++11)	computes cubic root (3√x) (function)
pow	raises a number to the given power (xy) (function)